"They are all part of one nation - one nation working together to get on. That is the nation we represent. These are the people I serve as Chancellor," he said.

He added: "To the people of Britain I say this. Whoever you are, wherever you come from, if you're working for a better future - we are on your side."

Mr Osborne asked for the party's "trust" and "resolve" as he issued a stark warning about the huge challenges ahead.

"It isn't too much to say that the future prosperity of our country, the future of a free enterprise system under law, even the stability of Europe (Chicago Options: ^REURUSD - news) , is in question in a way it has not been in my lifetime," he said.

"I cannot pledge to you simple answers or a quick solution. This year has shown we are a country confronted on all sides by great difficulties.

"But this year has also shown we live in a country of courage and creativity. A country that can do incredible things and succeed when we pull together."

The address in Birmingham followed a Sky News poll by Ipsos Mori showing just 27% of people are satisfied with the Chancellor's performance - his lowest ever personal rating.

Meanwhile, London Mayor Boris Johnson was greeted by passers-by chanting "Boris! Boris!" as he arrived at the conference to address a fringe event later organised by the Conservative Home website called Re-elected and Olympotastic, and to deliver a keynote speech on Tuesday.

Mr Johnson has been touted as a possible alternative to David Cameron as Conservative leader.

Asked if he was in Birmingham to make trouble for Mr Cameron, Mr Johnson replied: "I'm here to support the party."